1) Annihilate 2) Chew up 3) Eradicate 4) Kill 1) BBC television game show 2) Destroy a large part of 3) Destroy en masse 4) Kill 5) Kill every tenth man 6) Kill in large numbers 7) Nearly wipe out 8) Ravage 9) Reduce drastically 10) To destroy a large portion 11) To take a tenth of or from 
• (v. t.) To select by lot and punish with death every tenth man of; as, to decimate a regiment as a punishment for mutiny. • (v. t.) To take the tenth part of; to tithe. • (v. t.) To destroy a considerable part of; as, to decimate an army in battle; to decimate a people by disease.
1. To take the tenth part of; to tithe. ... 2. To select by lot and punish with death every tenth man of; as, to decimate a regiment as a punishment for mutiny. ... 3. To destroy a considerable part of; as, to decimate an army in battle; to decimate a people by disease. ... Origin: L. Decimatus, p. P. Of decimare to decimate (in senses 1 & 2), ...
to destroy a large portion
Dec'i·mate transitive verb [ imperfect & past participle Decimated ; present participle & verbal noun Decimating .] [ Latin decimatus , past participle of decimare to decimate (in senses 1 & 2), from decimus tenth. ...
[v] - kill one in every ten of, as of mutineers in Roman armies
to destroy a great number or proportion of: The population was decimated by a plague. · to select by lot and kill every tenth person of. · to take a tenth of or from.
kill in large numbers kill in large numbers